Cooling seal

ABSTRACT

A mechanical seal assembly for a motor or pump shaft having a cooling fluid flow passage, and wherein the mechanical sealing elements are disposed in a seal chamber which communicates with the flow passage, the seal elements define with the shaft, a cooling fluid flow path extending internally of the seal elements.

United States Patent [191 Wiese [4 1 Apr. 23, 1974 COOLING SEAL [75]Inventor: Winfred J. Wiese, Whittier, Calif.

[73] Assignee: Borg-Warner Corporation, Chicago,

Ill.

[22] Filed: Oct. 4, 1972 [21] Appl. No.: 295,082

[52] US. Cl 277/15, 277/74, 277/93, 277/DIG. 8 [51] Int. Cl Fl6j 15/34[58] Field of Search 277/3, 15, 16, 71, 74, 277/93, DIG. 8

[56] References Cited UNITED STATES PATENTS 2,628,852 211953 Voytech..2'77 15 2,824,759 2/1958 Tracy 277/15 3,028,181 4/1962 Thompson etal..... 277/15 3,291,489 12/1966 Tracy et al 277/15 PrimaryExaminer-Louis R. Prince Assistant,Examiner-Robert 1. Smith Attorney,Agent, or Fir'm-Donald W. Banner 5 7] ABSTRACT A mechanical sealassembly for a motor or pump shaft having a cooling fluid flow passage,and wherein the mechanical sealing elements are disposed in a sealchamber which communicates with the flow passage, the seal elementsdefine with the shaft, a cooling fluid flow path extending internally ofthe seal elements.

9 Claims, 1 Drawing Figure COOLING SEAL BACKGROUND OF THE INVENTION-motor is operating is hot, such as in the case of various canned motorpump units which include a sealed motor pump assembly containing an oilbath in the motor, it has been the practice to provide a cooling fluidcirculating system for causing the flow of the oil in the motor througha cooling loop including a flow passage extending through the motorshaft from or adjacent to its juncture with the pump shaft. A mechanicalseal has been employed to confine the cooling fluid in a seal chamberdefined at the juncture of the motor housing and the pump housing. Theseprior seals have included a bellows and a pair of seal rings havingcompanion radial sealing faces confining the cooling fluid in the sealchamber, one of the seal rings and the bellows being non-rotatable andthe other seal ring bein rotatable with the motor shaft.

Such cooling seal assemblies, while being, in general satisfactory, haveposed problems respecting their reliability due to variations in thebellows and complexity of assembly, disassembly and repair, and due tothe cooling fluid being internally confined by the seal rings wherebythe seal is subjected to pressure causing tensile stress in the sealrings.

SUMMARY OF THE INVENTION The present invention provides a seal for motorpump shaft cooling systems of the general type referred to above, butwherein the seal is reliable and is easy to assemble and disassemble. Inaddition, the seal of the present invention is so constructed andarranged that the cooling fluid pressure is applied externally, that is,to the outer periphery of the seal rings, so that the seal rings areunder compressive force and therefore more reliable.

In accomplishing the foregoing, the present invention provides astationary seal ring having a radial seal face and fixedly disposed in aseal flange so as to be exposed to atmosphere at its inner peripheryabout a supporting sleeve for a rotatable seal ring, the supportingsleeve being effectively connected to the shaft for rotation therewithand extending into a seal chamber which communicates with a coolingfluid passage in the shaft internally of the supporting sleeve, Therotatable seal ring has a radial seal face opposed to the seal face ofthe non-rotatable seal ring, so that cooling fluid is confined withinthe seal chamber and flows to the cooling fluid passage in the shaft.With such a construction, the supporting sleeve, with the rotatable andnon-rotatable seal ring thereon is easily installed on the shaft andretained thereon by a retainer ring. Since the fluid pressure is appliedexternally or at the outer periphery of the seal rings and applies acompressive radial force thereto, the seal efficiency is enhanced.

This invention possesses many other advantages, and has other purposeswhich may be made more clearly apparent from a consideration of a formin which it may be embodied. A form is shown in the drawing accompanyingand forming part of the present specification. It will now be describedin detail, for the purpose of illustrating the general principles of theinvention;

but it is to be understood that such detailed description is not to betaken in a limiting sense, since the scope of the invention is bestdefined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWING The single view of the drawing is afragmentary view partly in longitudinal section and partly in elevation,showing a seal according to the present invention applied to a shaft ofa motor-pump assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in the drawing a motorhousing M has a shaft opening 10 in which is rotatably disposed a motorshaft ll. Affixed to the motor housing M is a typical mechanical sealflange 12, secured in place by a suitable number of screw fasteners 13and having a suitable ring seal 14 to prevent leakage between the motorhousing M and seal flange 12. In the present illustration, the motorshaft 11 is joined to a reduced diameter pump shaft 15 which isrotatably disposed within a pump housing P. The present invention is notconcerned with the details of the Motor M or the pump P and thereforeonly the adjacent portions of the respective housings are hereinillustrated, and the illustrated structure is substantiallyconventional, including the manner in which the motor shaft 11 is joinedto the pump shaft 15 and the manner in which cooling fluid is circulatedthrough the motor shaft 11, as will be later described.

More particularly, however, the motor shaft 11 has a reduced end portion16 which is disposed within a bore 17 of the pump shaft 15, and theshafts are interconnected by suitable means, such as a weld designated18. The reduced end portion 16 of the motor shaft 11 is provided with afurther reduced section 18' having helical ribs 19 thereon extendingbetween the end extremity of the reduced section 18' and an annularspace or fluid passage 20 between the end section 18' of the motor shaftand the reduced section 16 thereof. The pump shaft 15 has a suitablenumber of radial ports 21 which communicate with the annular space 20and with the seal chamber 22 which is defined between the shaft assemblyand the motor housing M and the seal flange 12.

A cooling fluid such as oil is adapted to be supplied to the sealchamber 22 through a suitable inlet port 23 in the motor housing M,leakage of such cooling oil from the chamber 22 between the seal flange12 and the pump shaft 15 being prevented by a mechanical seal assemblyS, hereinafter to be described. However, the flange 12 may have theinlet port, or fluid passage, opening into the seal chamber 22, throughwhich cooling fluid may be supplied to the seal chamber. The cooling oilentering the seal chamber 22 is adapted to flow, via the ports 21 in thepump shaft 15, into the annular space 20 and thence between the helicalribs 19 through the annular space 24 defined between the reduced end 18'of the motor shaft 1 1 and the pump shaft bore 25 into which the motorshaft end 18' extends. Extending longitudinally through the motor shaft11 is a coolant fluid passage 26 having an opening 27 at its end whichopens in the bore 25, whereby fluid flowing between the helical ribs 19finds access to the longitudinally extended passage 26. The passage 26,as is well known may lead to the motor shaft thrust bearings in anaxially spaced remote location, so as to cool the latter, and due to thepath of circulation of the cooling fluid, which is supplied from asuitable pumping source, between the helical ribs 19, the contiguousportions of the pump shaft are also effectively cooled, so that if thepump is handling hot fluids, then the heat is prevented fromtransferring through the shaft connection to the motor.

The general assembly, as thus fair described, is substantiallyconventional in so called canned motors, wherein the cooling fluid oroil is re-circulated through the motor shaft to perform its coolingfunction. The

present invention relates to the novel seal assembly S in such a motorpump assembly.

The present seal assembly S includes a non-rotatable seal ring disposedwithin a bore 31 in the seal flange 12, with a suitable resilientsealing ring 32 interposed between the flange l2 and the seal ring 31 toprevent leakage about the exterior of the seal ring 30. The seal ring 30has a radially extended flat seal face 33 opposed by a companion radialflat sealing face 34 of a rotatable seal ring 35 which is adapted torotate with the shaft and to be biased axially by fluid pressure towardthe non-rotatable seal ring 30 to control leakage between the opposedseal faces 33 and 34, as is typical in mechanical seals.

The rotatable seal ring 35 is supported at its inside diameter on acylindrical shoulder or balance portion 36 of a supporting sleeve 37,which, as will be later described, is mounted upon the shaft assemblyfor rotation therewith. The supporting sleeve 37 has an inner end flange38 projecting radially outward and constituting an abutment engageableby a drive ring 39 which is pinned or otherwise suitably connected tothe supporting sleeve 37 by means of one or more circumferentiallyspaced pins 40 which engage in elongated slots 41 in the drive ring-39,whereby rotation of the supporting sleeve 37 is transmitted to the drivering 39, but the drive ring 39 can be assembled end-wise over thebalance portion 36 of the supporting sleeve 37.

The drive ring 39 is also adapted to drive a seal carrier ring 42, bymeans of suitable drive pins 43 carried by the drive ring 39 andprojecting radially outwardly into longitudinally extended slots 44 inan outer cylindrical portion 45 of the carrier ring 42. The carrier ring42 has an inner cylindrical portion 46 slidably disposed upon thebalance portion 36 of the supporting sleeve 37, and projecting into anannular peripheral groove 48 in the rotatable seal ring 35, in which isdisposed a suitable resilient sealing ring 49, adapted to form a sealbetween the supporting sleeve 37 and the rotatable seal ring 35, wherebycooling fluid or oil in the seal chamber 22 may not escape therebetween.A suitable number of longitudinally extended and cir'cumferentiallyspaced drive lugs 50 on the rotatable seal ring 35 are engaged in theslots 44 of the seal carrier ring 42, whereby rotation of the carrierring 42 is transmitted to the rotatable seal ring 35. i

In order to connect the seal supporting sleeve 37 to the shaft assembly,while at the same time facilitating assembly of the seal assembly Swithin the seal chamber 22, the seal supporting sleeve has an internalflange 51 adapted to abut with a radially outwardly projecting shoulder52 on the shaft assembly, in the embodiment shown on the pump shaft 15.Engaged between the shaft and the flange 51 is a sealing ring 51a whichprevents leakage of cooling fluid between the shaft and supportingsleeve 37. The supporting sleeve 37 is retained in place, with theinternal flange 51 abutting with the shoulder 52, by a retainer sleeve53 which is suitably threaded at 54 onto the pump shaft 15 and locked inplace by a set screw 54a, and whichhas an end section 55 adapted to abutwith the supporting sleeve flange 51 to hold it against the shaftshoulder 52. An end portion 56 of the supporting sleeve 37 extendsaxially through the non-rotatable seal ring 30 and has an outsidediameter smaller than the inside diameter of the non-rotatable seal ring30 and smaller than the inside diameter of the rotatable seal ring 35,as well as the drive and carrier rings 39 and 42, whereby the sealcomponents may be installed end-wise upon the supporting sleeve 37, andthereafter retained in place against displacement from the supportingsleeve 37 by means of a retainer ring 57 suitably affixed to thesupporting sleeve portion 56 by one or more set screws 58. This retainerring 57 maintains the various components previously described inassemblyv and against being moved end-wise along the supporting sleeve37 before assembly within the seal chamber, so that a suitable number ofcoiled compression springs 59, seating in bores 42, are retained inplace. These springs 59 are employed to provide initial sealing contactbetween the seal faces 33 and 34.

It will be apparent that when the seal flange 12 is removed from themotor housing M, the entire rotatable component of the seal assembly Scan be removed endwise, to the right as seen in the drawing for removalfrom the shaft assembly and replacement rotatable seal assemblies may beeasily installed.

In addition it will be noted that the seal chamber 22 communicates withthe ports 21, and thence with the cooling fluid passageway 26 in theshaft assembly, through a passage 37a defined between the insidediameter of the supporting sleeve 37 and the outside diameter of theshaft assembly, formed as elongated slots in the inside wall of thesupporting sleeve 37, and then via an annular space 37b defined betweenthe supportnon-rotatable seal ring 30, so that as rotation ofthesupporting sleeve 37 occurs such leakage will be thrown radiallyoutwardly by centrifugal force and thereby not drain into the pumphousing P, which in the presence of hot pump fluids may be so hot as tocause coking, for example, in the case of cooling oil.

In addition, inasmuch as-the pressure of cooling fluid within the sealchamber 22 is applied to the outer peripheries or the outside diametersof the seal rings 30 and 35, the seal rings are subjected to acompressive force and are thereby more effective in their sealingaction, than is the case when seal rings are subjected to the pressureof fluid being sealed at the inside diameters of the seal rings.

From the foregoing it will be apparent that the present inventionprovides a simple seal assembly adapted for use in cooling systems formotor pump assemblies, wherein the seal assembly may be readilyinstalled and removed and wherein the seal assembly is more effectiveand reliable in that the pressure of cooling fluid is applied in such amanner as to maintain the seal rings under compression.

I claim:

1. In a mechanical sealing assembly; a housing having a shaft opening, ashaft rotatable in said opening, a seal flange on said housing and alsohaving a shaft opening in which said shaft is rotatable, said housing,said flange and said shaft defining a seal chamber, said shaft having afluid passage opening into said seal chamber, one of said housing andflange having a fluid passage opening into said seal chamber, saidmechanical sealing means in said seal chamber for confining fluid insaid chamber to a flow path between said fluid passages: the improvementwherein said mechanical sealing means includes a non-rotatable seal ringcarried by said flange and encircling said shaft in circumferentiallyspaced relation to said shaft, a rotatable seal ring in said chamber,said seal rings having opposed sealing faces extending radially, andsupporting means supporting said rotatable seal ring in said chamber andconnecting said rotatable seal ring to said shaft for rotationtherewith, said supporting means and said shaft defining a flow paththerebetween communicating between said fluid passages.

2. In a mechanical sealing assembly as defined in claim 1, said housinghaving said fluid passage opening into said seal chamber.

3. In a mechanical sealing assembly as defined in claim 1, saidsupporting means supporting said rotatable seal ring in said chambercomprising a sleeve disposed about said shaft, and means connecting saidsleeve to said shaft.

4. In a mechanical sealing assembly as defined in claim 1, saidsupporting means supporting said rotatable seal ring in said chambercomprising a sleeve disposed about said shaft, and means connecting saidsleeveto said shaft, said sleeve having an enlarged diameter portionsupporting said rotatable seal ring thereon, and including sealing ringmeans between said enlarged diameter portion and said rotatable sealring to prevent passage of fluid therebetween.

5. In a mechanical sealing assembly as defined in claim 1, saidsupporting means supporting said rotatable seal ring in said chambercomprising a sleeve disposed about said shaft, and means connecting saidsleeve to said shaft, said sleeve having an enlarged diameter portionsupporting said rotatable seal ring thereon, and including sealing ringmeans between said enlarged diameter portion and said rotatable sealring to prevent passage of fluid therebetween, and drive means forrotating said rotatable seal ring with said sleeve.

6; In a mechanical sealing assembly as defined in claim 1, saidsupporting means supporting said rotatable seal ring in said chambercomprising a sleeve disposed about said shaft, and means connecting saidsleeve to said shaft, said sleeve having an enlarged diameter portionsupporting said rotatable seal ring thereon, and including sealing ringmeans between said enlarged diameter portion and said rotatable sealring to prevent passage of fluid therebetween, and drive means forrotating said rotatable seal ring with said sleeve while enablinglimited longitudinal movement of said rotatable seal ring with respectto said sleeve and said non-rotatable seal ring.

7. In a mechanical sealing assembly as defined in claim 1, saidsupporting means supporting said rotatable seal ring in said chambercomprising a sleeve disposed about said shaft, and means connecting saidsleeve to said shaft, said sleeve having an enlarged diameter portionsupporting said rotatable seal ring thereon, and including sealing ringmeans between said enlarged diameter portion and said rotatable sealring to prevent passage of fluid therebetween, and drive means forrotating said rotatable seal ring with said sleeve while enablinglimited longitudinal movement of said rotatable seal ring with respectto said sleeve and said non-rotatable seal ring, and spring means forbias ing said rotatable seal ring towards said non rotatable seal ring.

8. In a mechanical sealing assembly as defined in claim 1, saidsupporting means supporting said ro'tatable seal ring in said chambercomprising a sleeve disposed about said shaft, and means connecting saidsleeve to said shaft including a shoulder on said shaft, and a connectorsleeve threadedly connected to said shaft and engaged with saidsupporting sleeve to force said supporting sleeve against said shoulder.

9. In a mechanical sealing assembly as defined in claim 1, saidsupporting means supporting said rotatable seal ring in said chambercomprising a sleeve disposed about said shaft, and means connecting saidsleeve to said shaft including a shoulder on said shaft, and a connectorsleeve threadedly connected to said shaft and engaged with saidsupporting sleeve to force said supporting sleeve against said shoulder,and means interconnecting said supporting sleeve and said connectorsleeve against relative rotation.

UNITED STATES PATENT GlFFICE CERTIFICATE OF CORRECTION Patent No. 3 I 6a 135 Dated April 23 1974 Winfred J. Wiese Inventor(s) It is certifiedthat error appears in the above-identl I led patent and that saidLetters Patent are hereby corrected as shown below:

Column 5; line 10, before "flange" insert said line 11, "said", vsecondoccurrence, should be deleted i Signed and sealed this 29th day ofOctober 1974.

(SEAL) Attest:

McCOY M; GIBSON JR. 0. MARSHALL DANN Attoating Officer Commissioner ofPatents FORM pomso (169) USCOMM-DC wens-pea u.s GOVERNMENT PRINTINGOFFICE: 930

1. In a mechanical sealing assembly; a housing having a shaft opening, ashaft rotatable in said opening, a seal flange on said housing and alsohaving a shaft opening in which said shaft is rotatable, said housing,said flange and said shaft defining a seal chamber, said shaft having afluid passage opening into said seal chamber, one of said housing andflange having a fluid passage opening into said seal chamber, saidmechanical sealing means in said seal chamber for confining fluid insaid chamber to a flow path between said fluid passages: the improvementwherein said mechanical sealing means includes a non-rotatable seal ringcarried by said flange and encircling said shaft in circumferentiallyspaced relation to said shaft, a rotatable seal ring in said chamber,said seal rings having opposed sealing faces extending radially, andsupporting means supporting said rotatable seal ring in said chamber andconnecting said rotatable seal ring to said shaft for rotationtherewith, said supporting means and said shaft defining a flow paththerebetween communicating between said fluid passages.
 2. In amechanical sealing assembly as defined in claim 1, said housing havingsaid fluid passage opening into said seal chamber.
 3. In a mechanicalsealing assembly as defined in claim 1, said supporting means supportingsaid rotatable seal ring iN said chamber comprising a sleeve disposedabout said shaft, and means connecting said sleeve to said shaft.
 4. Ina mechanical sealing assembly as defined in claim 1, said supportingmeans supporting said rotatable seal ring in said chamber comprising asleeve disposed about said shaft, and means connecting said sleeve tosaid shaft, said sleeve having an enlarged diameter portion supportingsaid rotatable seal ring thereon, and including sealing ring meansbetween said enlarged diameter portion and said rotatable seal ring toprevent passage of fluid therebetween.
 5. In a mechanical sealingassembly as defined in claim 1, said supporting means supporting saidrotatable seal ring in said chamber comprising a sleeve disposed aboutsaid shaft, and means connecting said sleeve to said shaft, said sleevehaving an enlarged diameter portion supporting said rotatable seal ringthereon, and including sealing ring means between said enlarged diameterportion and said rotatable seal ring to prevent passage of fluidtherebetween, and drive means for rotating said rotatable seal ring withsaid sleeve.
 6. In a mechanical sealing assembly as defined in claim 1,said supporting means supporting said rotatable seal ring in saidchamber comprising a sleeve disposed about said shaft, and meansconnecting said sleeve to said shaft, said sleeve having an enlargeddiameter portion supporting said rotatable seal ring thereon, andincluding sealing ring means between said enlarged diameter portion andsaid rotatable seal ring to prevent passage of fluid therebetween, anddrive means for rotating said rotatable seal ring with said sleeve whileenabling limited longitudinal movement of said rotatable seal ring withrespect to said sleeve and said non-rotatable seal ring.
 7. In amechanical sealing assembly as defined in claim 1, said supporting meanssupporting said rotatable seal ring in said chamber comprising a sleevedisposed about said shaft, and means connecting said sleeve to saidshaft, said sleeve having an enlarged diameter portion supporting saidrotatable seal ring thereon, and including sealing ring means betweensaid enlarged diameter portion and said rotatable seal ring to preventpassage of fluid therebetween, and drive means for rotating saidrotatable seal ring with said sleeve while enabling limited longitudinalmovement of said rotatable seal ring with respect to said sleeve andsaid non-rotatable seal ring, and spring means for biasing saidrotatable seal ring towards said non - rotatable seal ring.
 8. In amechanical sealing assembly as defined in claim 1, said supporting meanssupporting said rotatable seal ring in said chamber comprising a sleevedisposed about said shaft, and means connecting said sleeve to saidshaft including a shoulder on said shaft, and a connector sleevethreadedly connected to said shaft and engaged with said supportingsleeve to force said supporting sleeve against said shoulder.
 9. In amechanical sealing assembly as defined in claim 1, said supporting meanssupporting said rotatable seal ring in said chamber comprising a sleevedisposed about said shaft, and means connecting said sleeve to saidshaft including a shoulder on said shaft, and a connector sleevethreadedly connected to said shaft and engaged with said supportingsleeve to force said supporting sleeve against said shoulder, and meansinterconnecting said supporting sleeve and said connector sleeve againstrelative rotation.